MacDonald Logan C, Weiler Elizabeth B, Berger Bryan W
Program in Bioengineering, Lehigh University, B320 Iacocca Hall, 111 Research Drive, Bethlehem, PA 18015 USA.
Program in Bioengineering, Lehigh University, B320 Iacocca Hall, 111 Research Drive, Bethlehem, PA 18015 USA ; Department of Chemical and Biomolecular Engineering, Lehigh University, B320 Iacocca Hall, 111 Research Drive, Bethlehem, PA 18015 USA.
Biotechnol Biofuels. 2016 Feb 24;9:43. doi: 10.1186/s13068-016-0455-8. eCollection 2016.
Macroalgae represents a promising source of fermentable carbohydrates for use in the production of energy efficient biofuel. The primary carbohydrate in brown algae is the uronic acid-containing alginate, whereas green algae contains a significant amount of glucuronan. A necessary step in the conversion of these polyuronides to bioethanol is saccharification, which can be achieved by enzymatic or chemical degradation.
Polysaccharide lyases are a class of enzymes which cleave uronic acid-containing glycans via a β-elimination mechanism, acting both endo- and exolytically on their substrates. In the present work, we characterize a putative alginate lyase from Stenotrophomonas maltophilia K279a (Smlt2602) and describe a H208F mutant that, in addition to cleaving alginate-based substrates, displays significant, exolytic glucuronan activity.
To our knowledge this is the first polysaccharide lyase to act exolytically on glucuronan and is an attractive candidate for the broad-spectrum digestion of polyuronides into fermentable monomers.
大型藻类是用于生产高能效生物燃料的可发酵碳水化合物的一个有前景的来源。褐藻中的主要碳水化合物是含糖醛酸的藻酸盐，而绿藻含有大量的葡糖醛酸聚糖。将这些聚糖醛酸转化为生物乙醇的一个必要步骤是糖化，这可以通过酶促或化学降解来实现。
多糖裂解酶是一类通过β-消除机制切割含糖醛酸聚糖的酶，对其底物同时具有内切和外切作用。在本研究中，我们鉴定了嗜麦芽窄食单胞菌K279a（Smlt2602）中的一种假定藻酸盐裂解酶，并描述了一种H208F突变体，该突变体除了能切割基于藻酸盐的底物外，还表现出显著的外切葡糖醛酸聚糖活性。
据我们所知，这是第一种对外切葡糖醛酸聚糖起作用的多糖裂解酶，是将聚糖醛酸广泛消化成可发酵单体的有吸引力的候选酶。
